Process and apparatus for handling elastic filamentary material



April 1943. J. M. LEACH- 2,317,921

PROCESS AND APPARATUS FOR HANDLING ELASTIC FILAMENTARY MATERIAL Filed March 21, 1941 Con/mourn .3 r

INVENTOR Patentccl Apr. 27, 1943 PROCESS AND APPARATUS FOR HANDLING ELASTIC FILAMENTABY MATERIAL John M. Leach, Fredcrlcirsburg, Va., assignor to Filatex Corporation, New York, N. 1., a corporation of New Jersey Application March 21, 1941, Serial No. 384,514

11 Claims. (Oi. 28-715) The present invention relates to the handling oi filamentary materials. More particularly, it relates to the feeding of filamentary materials which are elastic in nature.

Elastic filamentary material, for example bare or covered elastic rubber thread, presents many problems in handling which are peculiar to elastic materials alone. For example, when such materials are formed into a package such as by being wound upon a spool, cone, swift or the like. convolutions frequently become embedded in adjacent convolutions and when the filamentary material is pulled ofi. of the spool the embedded convolutions cause the material to hang or stick upon the package and create excessive tension in that portion of the material directly in advance of the convolutions which are obstructed. It follows as a natural consequence of this action that elastic filamentary material being fed to various machines such as knitting machines, winders, bralders, covering machines and the like will be fed at an uneven tension and extension due to the sticking of the filamentary material upon the supply package. Many attempts have been made to overcome this problem and much work has been spent in devising instrumentalities intended to eliminate or compensate for the uneven tension created in feeding elastic filaments.

One of the earliest expedients utilized in an attempt to eliminate the uneven feeding tension problem was to feed elastic filamentary material from the original. supply package into an open top container in loose convolutions so as to eliminate all the tension from the filamentary material. This feature is illustrated by U. S. Patent No. 1,775,033. It was found, however, that the convolutions within the container were liable to snarl and knot together and lodge in the first opening encountered such as an eyelet, pulley. needle or the like and caused breakage of the filament and stoppage of the machine.

Another scheme that has been advanced in an eifort to control the tension in an elastic filament being fed to some using device is to passthe filament between two pairs of positively driven feed rolls so as to form a loop in the filament between the feed rolls; the flrst pair of feed rolls contacted by the filamehtlbelng constructed so as to have their effective peripheral speed varied by a suitable mechanism. A pulley is mounted for rotation on the end of a pivoted lever to which a weight is attached or which is itself weighted and the pulley is suspended in the loop of the filament. Variation in the tension at the filament in the loop raises or lowers the pulley and moves the arm about its pivot and through a suitable linkage varies the effective speed of the first pair of feed rolls so as to redues or increase the amount of the elastic fila ment being fed into the loop a suflicient amount to bring the weighted pulley back to its original position. A device of this type is illustrated in U. 8. Patent No. 1,962,029. The theory of operation of this device in general is that the tension of the elastlc filament forming the loop will be maintained substantially constant by the action of the weighted pulley in raising and lowering as the tension varies so as to increase and decrease the speed of the first feed rolls and thus feed in more or less elastic filament to compensate for tension variations in the filament passing between the first pair of feed rolls. In such devices a tension compensation may not take place until after there has been a variation in tension and the variation in tension which is later compensated for is sometimes present in the elastic filament which is ultimately fed to the using device.

Another apparatus which has been designed in an attempt to assure feeding of elastic filaments under uniform tension is illustrated by U. S. Patent No. 2,158,547. This device operates in general upon the well known principle of snubbing several turns of a rope around a rotating winch so as to transmit the power exerted by the winch to that end of the rope running onto the winch through friction between the winch and the several turns of rope about the winch caused by the application of a moderate pull by the operator upon the end of the rope running 011 of the winch.

The device comprises a pair of positively driven feeding wheels which are provided with smooth surfaces. The feeding wheels are rotated at a surface speed slightly in excess of the desired feeding speed for the elastic filament. The elas-' tic filament is led all of a supply source, such as a spool or the like, and passed around the feeding wheels several times and then led to a using device such as a knitting machine. When the elastic filament runs freely from the spool or cone and freely into the using device it will not be snubbed very tightly about the feeding wheels and they will not exert an appreciable tractive effort on the filament. In case the filament should stick at the spool it will be snubbed about the feeding wheels tightly enough to be more or lessposltlvely advanced by the same a suillclent amount to overcome the sticking. Any increase in tension between the feeding wheels and the using device will also cause snubbing of the filament about the wheels which will feed the filament and relieve the tension. Here a variation in tension must take place before the mechanism can be put into operation to compensate for variation in tension.

Another type of device for the intended purpose of feeding elastic yarn under uniform tension is illustrated by U. S. Patent No. 2,169,699. This device is somewhat in the nature of a combination of two of the previously described devices and comprises an electric motor for driving an elastic filament feeding drum and which is operated by a switch carried by a pivoted arm having an eyelet at the i'ree end which hangs in a loop formed in the elastic filament. The elastic filament is fed from a supply spool or the like and is passed over a bent wire guide positioned immediately above the lead drum and then around the drum and then around another portion or the bent wire guide and then again around the drum until several turns have been taken about the gulde and drum. The filament is led from the guide through the arm eyelet and then to a using device. Whenever suillcient tension is exerted on the filament by the using device the arm will be raised .to start the motor and suflicient tension is at the same time placed upon the elastic filament in the turns on the drum and guide to enable the drum to advance the filament suiilciently to lowerthe arm and therebyopen the switch to stop the feed of the yarn. Here again the elastic filamentary material is not fed at a constant tension since it is again necessary for a tension variation to take place in the filament at the using device before the compensating function of the machine is set in operation.

The first process and apparatus. to actually accomplish the feeding of elastic'fiiamentary material under anabsolutely constant tension is illustrated by U. S. Patent No. 2,199,550. The apparatus disclosed by this patent comprises a pair of feed rolls or the like for drawing an elastic filament irom a supply source such as a'swift.

From these rolls the filament is passed into a: freely suspended loop in which the-elastic fiia-' ment is permitted to entirely relax so as to re move all tension from it, except the inconse quential amount caused by the weight of the filament within the loop whichcan be maintained so low by controlling the size of the loop as to never stretch the filament and which can be disregarded.

From the loop the filament is passed in a uniform state of tension to any desired using apparatus.

Although the device lust described succeeded in feeding elastic filamentary material to various using devices under uniform tension, the period over which the device is operable limited due to the fact that the elastic filament forming the loop is rapidly shortened whenever'a very poor package is used, for example a spool, swift or cone containing filament wound under a tensionlng varying between wide limits and/or in which many of the'tums are buried between adjacent turns. This condition arises because constant hanging of the filament of the package increases the tension in the filament between the package and the first supply rolls to such an extent that constant relaxlng'of the filament as it'passes into the loop gradually uses all of the fiiament out of the loop and thereby decreases the size of the loop. 'When such condition. occurs, it is, of course, necessary to stop the machine and reestablish the loop. The present invention overcomes this undesirability and makes it possible to operate indefinitely or until a package is exhausted without stopping the machine. .3

It is an object of the present invention to-provide a process for continuously feeding. elastic filamentary material to any desired uslng device under uniform tension.

It is another object of the present invention to provide a process for feeding elastic filamentary provide an apparatus capable of carrying out the process of the invention.

Other objects and advantages will be apparent to those skilled in the art from recourse to the following detailed description of the invention.

The invention in general provides a process and apparatus whereby the size of a loop of relaxed elastic filamentary material In the length of a filament being led to s. using device may be controlled without exerting a stretching tension on the material within the loop so as to thereby continuously teed elastic material to the using device in a uniform state of tension.

The invention accordingly comprises the several stepsand the relation of one or more such steps with respect to each of the others, and the apparatus. embodying features of construction, combinations of elements and arrangement of parts which are adapted to eilect such steps, all as exemplifledln the lollowlng detailed disclosure, and the scope of the invention will be indicated in the claims.

For a fuller understanding oi the nature and objects of the invention reference should be had to the following detailed description taken in connection with the accompanying drawing, in which:

Fig. 1 is a diagrammatlcal illustration of one form of apparatus oi the invention which is capable of use in practicing the method of the invention;

Fig. 2 is a fragmentary diagrammatlcal view of a modification of the apparatus of Fig. l, and

Fig. 3 13a sectional view of the apparatus of Fig. Ztaken substantially on the plane indicated by the llne 3- -3 and looking in the direction oi the arrows.

Referring to Fig. l, the apparatus comprises a pair of positively driven feed rolls I which are suitably connected to be driven together by a suitable driving mechanism, for example, pulleys 8 and a crossed belt 8. l'ntermeshing gears (not shown) and the like may be used instead of the belt if desired. The rolls 4 may be suitably urged toward each other under a controlled pressure by any suitable pressure exerting mechanism of well known type which within itself iomis no part of the present invention. The-feed rolls 4 are driven from asuitable source of power, such as an electric motor M through the medium of a pulley It on the motor, a second belt groove on the pulley G and a wrapping connector I! which is shown as a belt but may be a chain or the like. Other suitable driving lnstrumentalities, such as lntermeshlng gears or the like may be used if desired, or the motor shaft may be coupled directiyto the shaft of either oi the feeding rolls 4; a

Elastic filamentary material F is led from a supply spool H or the like and is passedlbetween the feed rolls'land is then ermitted to [all into a loop L from which it is passed between a second pair of positively driven feed rolls it which may be driven from anysuitable power source from a separate power source. as desired. The

feed rolls ll may also be urged together under a controlled pressure me similar manner to the rolls 4. Other suitable filament let-oil devices,

such as a tensioning comb and the like. may be used in the place of the rolls it when such is desired. The rolls 4 provide a first feeding zone. the rolls i6 provide a second feeding zone and the loop in between provides a zone of relaxation.

A delicately balanced blade switch 8 is positioned so that the blade I! thereof will be contacted by the lower portion of the loop L. The blade i8 is of sufficient width so that the filament will run on the upper surface and is suitably pivoted upon jewel bearings, needle hearings or any other well known type of minimum friction bearing and is urged upwardly under the extremely light pressure of a delicate, suitably adjustable coil spring 20. Any other well known type oi biasing mechanism may be used in plac of the spring 20. The end of the blade i8 opposite to the pivot co-acts with a switch point 22 to form a make and break switch to shut a resistance R of predetermined value in and out of the energizing circuit 24 for the motor M. The circuit 24 is connected to any suitable source oi electrical power P of a. type dependent upon the type of motor used for the motor M.

In the operation of the apparatus, the speed of rotation of the feed rolls i6 is first suitably adjusted so as to supply the ellistic filament F to the using device at any desired speed to furnish the elastic filament to the using device under no tension or under any desired tension within the limits of the modulus of elasticity of the elastic filament. The speed oi the motor M is then adjusted. as by manual adjustment of the rheostat 26 in the motor circuit, so as to drive the iced rolls 4 at any desired speed relative to the feed rolls It with the switch S open. Elastic filament F is then led from the supply spool i i, passed between the feed rolls 4 and the feed rolls i6 and formed between the pairs oi feed rolls into a. loop of such size as to cause the bottom to make light contact with the switch blade it and move the blade downwardly a sumcient distance to break contact with the switch point 22. The resistance offered by the spring 20 is suitably adjusted so that blade i8 will move under the light contact of the loop. The drive for the feed rolls i6 is then started and the motor circuit 241s energized to cause elastic filament to be led from th supply spool l4 through the feed rolls 4 into the loop L where the filament is permitted to entirely relax and assume a zero tension, and is then passed through feed rolls l6 to the using device.

Whenever there is sticking oi the elastic filament E upon the spool H the tension the filament between the spool i4 and the feed rolls 4 will be increased due to stretching of the filament. This increase in tension will be carried along with the filament into the loop L where the filament will contract and relax so as to reduce the stretching tension to zero and in contracting will decrease the size of the loop L. Decreasing the size of the loop will permit the blade ill to raise and establish contact with the switch point 22 and shunt the resistor R out of the circuit and thereby increase the speed of the motor M so as to increase the speed of rotation oi the feed rolls 4 and feed elastic filament into the loop L at a greater rate than it is being withdrawn from the loop by the feed rolls It. This increases the size oi the loop and lowers it into contact with the switch blade I8 and opens the switch which places the resistor it back in the circuit and consequently reduces the speed of the motor so as to stop feeding more elastic filament into the loop L than is being fed out of the loop by the feed rolls II.

The speed of rotation oi the motor M may be adjusted so thatthe ieed rolls 4 will ieed substantially the same amount of filament into the loop L as is led out by the rolls it whenever the switch blade it is in lowered position to thereby prevent repeated operation of the switch 3 or, if desired, the speed of the-motor M may be set so as to cause the rolls 4 to feed a little less filament into the loop L than is led out by the rolls it whenever the loop is lowered so as to open the switch. This causes the loop Lto be constantly alternately decreased and increased in size so as to hold the loop at a definite average size. By accurate adjustment oi the motor speeds it is possible to prevent the size of the'loop L from varying appreciably so that it is held at a substantially constant size.

It is to be understood that variation in the size of the loop L in an amount suificient to cause operation oi the switch it never causes the filament to stretch. This is true even though the changes in size of the loop take place rapidly to compensate for sudden tension variations in the filament beiore it enters the loop. This results in the filament always feeding into the rolls IS in a relaxed state. By "relaxed" is meant entirely free from stretch.

A modification oi the apparatus of the invention illustrated in Fig. 2 makes it possible to accurately control the size of the loop L without necessitating the movement of any physical .object through contact with the loop. In this modification, the loop L is suspended by the rolls 4 and it so as to tail between an aperture 20 of a housing 22 containing a suitable light source 3, and the aperture 35 of a housing 18 containing any well known type of photo-elecltrlc cell 40. The photo-electric cell 40 is connected by means of suitable connectors 42 to a controller 44 for varying the resistance in the motor circuit 24 for motor M. Controller 44 is of a type well known in the art and consequently need not be described in detail beyond stating that variation in the resistance of the light cell 40 due to the decrease or increase in the amount of light received by the cell from the light 24 operates the controller 44 to vary the resistance of the motor circuit 24 so as to vary the speed of the motor M. The controller 44 is adjusted so that when the loop L is in position between the apertures 30 and 28 so as to reduce the amount of light being supplied to the cell 40 lrom the light source 24, the resistance of the motor circuit 24 will be such that the speed of the motor M is such as to drive the rolls 4 at the same speed as the rolls i6 and hold the lower portion of the loop in position between the apertures 30 and It. When the size of the loop L under these conditions is decreased due to variation in the tension of the filament 1" coming from the spool I4 or the like, the lower portion oi the loop will move upwardly from between the apertures Ill and 36 and the resistance oi the light cell will be varied due to the increase in the light coming from the light source 34, and the resistance of the motor circuit' 24 will be proportionally varied and increase the speed oi the motor M to feed more filament F into the loop L and thereby increase its size until the lower portion is again positioned between the apertures Ill and 35 to decrease the light reaching the cell 40 from the a light source 24. When this occurs the resistance m the motor circuit 24 is increased through the operation of the controller 44 and drops the speed of the motor so as to hold the loop L at the proper size until it is again decreased in size due to the variation in tension in the filament F as it leaves the spool. In this manner the stretching tension in the filament in the loop L is always maintained at zero and the size of the loop is always maintained. The controller may be suitably adjusted so that the speed of the motor M is maintained constant at such speed whenthe lower portion of the loop L is between the apertures as to hold the loop in this position, or the motor speed at this time may be made slightly less than that required to hold this size of loop with the result that theloop gradually shortens and in so doing increases the speed of the motor to again lengthen the loop and slow down the motor to the former speed. By making the controller adjustment sufiiciently fine it is possible to hold :the loop L to a substantially constant size.

Bars 45 are suitably positioned beneath the loop L as by connecting them directly to the housing 3! so as to support the loop in the event it is moved out from between the apertures so and ii for any reason. This would increase the speed of the motor M and when the loop is again released it would fall below the level of the apertures and cause the motor M to continue operation at the increased speed. When the bars II are present the loop will rest on the bars when oversize and obstruct the light and thereby decrease the speed of the'motor M. By carefully adjusting the speeds of the motor both when the loop L is between the apertures and I6 and when the loop L is raised above the level of the apertures and 36 it is possible to so hold the position of the loop L as to have the lower portion thereof sustained at a fraction of an inch above the bars 46 so that in normal operation of the device it is never necessary for the loop to come in contact with any physical object. Its function is then merely to intercept light passing through apertures 30 and 36. It can thus be seen that the stretching tension in the fila- 3 ment in the loop L will be maintained at zero at all times. A plate may be substituted for the bars 45 if desired.

Since air currents may swing the loop and thereby afiect operation of the control devices, it is advisable to construct a suitable bame, such as a casing or the like, around the loop. Since the loop is automatically maintained, the entire mechanism can be enclosed, if desired, leaving only a sufilclent opening to aiiord access for renewing the package, threading, cleaning and the like; which opening may be closed by a door or cover.

Suitable mechanical filament feeding mechanism can be operated by the switch 8 or cell lli through known control devices to vary the rate of feed of the filament passing into the loop without departing from the scope of the invention.

The present invention makes it possible to use elastic filaments on using devices which are extremely sensitive to tension variation, such as knitting machines, covering machines. winders, braiders, and looms. practically without regard to the type of package in which the filament is contained or the way in which the filament is laid upon the package. The tension in the filament while on the package can vary within wide limits and it can repeatedly hang or stick while leaving the package and still the filament supplied to the using device will be under a uniform tension. This results in a tremendous saving of time and in addition enables better and more uniform products to be produced.

The present invention is particularly useiul in supplying elastic filamentary material to a using device which operates to best advantage when the filament or filaments are stretched or extended a uniform amount. Since the filament is supplied to the using device under a zero extension, the using device can then impose an absolutel constant extension upon the filament.

The present invention may be used in the handling oi. any filamentary material, but finds the most advantageous use in connection with those materials having such a pronounced elastic nature as to make their handling peculiarly dinicult such, for example, as bare and covered rubber tread.

Since certain changes in carrying out the above process and in the constructions set iorth, which embody the invention, may be made without departing from its scope, it is intended that all matter contained in the above description or shown in the accompanying drawing shall be interpreted as illustrative and not in a limiting sense. 7

The invention having been described, what is ciaimedis:

l. A process for handling elastic filaments comprising pulling an elastic filament from a package which necessitates varying the tension in the elastic filament, feeding the elastic filament at a definite rate into a zone in which the elastic filament is permitted to contract to and at all times remain under a substantially zero tension, increasing the feeding of the filament in direct proportion to the amount of contraction of the filament within the zone, the filament Within said zone being free from any weight other than its own weight at all times, and feed- 31g the filament from said zone to a using opera- 2. A process for handling elastic filaments comprising feeding elastic filaments from a supply source through a first leading zone at a definite rate, passing the filament to a. second feeding zone while permitting the filament to continuously relax and establish a zone of substantially zero tension in the filament between the two feeding zones, whereby the extent of the filament in the relaxed zone will tend to decrease directly with the amount of relaxation, and utilizing the variation in the extent of the filament in the relaxed zone to increase the rate of feed oi the filament through the first feeding zone to restore the amount of the filament in the relaxed zone to the original amount, the filament within said relaxed zone being free from any weight other than its own weight at all times, and passing the filament from the second feeding zone to a using operation.

3. A process for handling elastic filaments comprising feeding an elastic filament from a supply source, passing the filament through a pair or feeding rolls operable at a variable peripheral speed, passing the filament through a. second pair of feed rolls operating at a definite peripheral speed, permitting the filament to fall into a loop between the two pairs of teed rolls so as to continuously relax the filament substantially to zero tension and in so doing decrease the size of the loop so as to vary the position of the lower extremity oi the loop, and utilizing the position oi the lower extremity of the loop to control the peripheral speed of the first pair of feed rolls.

4. A process for handling elastic filaments comprising passing an elastic filament from a supply source to a pair of feed rolls operable at a variable peripheral speed, passing the filament to a second pair of feed rolls driven at a definite peripheral speed, permitting the filament to continuously relax and fall into a loop between the two pairs of feed rolls. in which loop the tension of the filament is substantially zero, creating a light path adjacent to the lower extremity of the loop, positioning a light sensitive element relative to the light path so that the lower extremity of the loop will intercept the light path in one position and extend above the light path in a raised position, utilizing the element and a controller operated thereby to control the peripheral speed of the first pair of iced rolls whereby the speed is increased when the lower extremity is above the light path and is decreased when the lower extremity of the loop intercepts the light path and passing the filament Irom the second pair of iced rolls to 9. using operation.

5. An apparatus for handling elastic filaments comprising feeding means for removing an elastic filament from a supply source, an electric motor for driving said feeding means, a circuit for said electric motor including a speed controller having a make and break switch, a second feeding means for the elastic filament between which and the first feeding means the elastic filament is permitted to fall into a loop, the filament within said loop being free from any weight other than its own weight at all times, the lower extremity of said loop being in position to contact the electric switch when lowered, whereby said switch is opened to decrease the speed of the motor whenever the loop engages the switch and is closed to increase the speed of the motor when the loop breaks contact with the switch.

6. An apparatus for handling elastic filaments comprising means for supporting a supply of elastic filament, a pair of positively-driven contacting rotatable members for receiving the elastic filament therebetween and for pulling it from the supply, an electric motor for driving said rotatable members, a circuit for said electric motor including a speed controller having a make and break switch, a second pair of positivelydriven rotatable contacting members for receiving the filament therebetween and advancing the filament and between which and the first pair of rotatable members the elastic filament is permitted to fall into a loop, the lower extremity of which is in position to contact the electric switch when lowered, whereby said switch is actuated to decrease the speed of the motor whenever the loop engages the switch and actuated to increase the speed of the motor when the loop breaks contact with the switch.

'1. A process for handling elastic filaments of the type employed in the fabrication of textiles wherein substantial uniformity in physical characteristics of the filament is essential, comprising removing an elastic filament from its support whereon the elastic filament may exist in a nonuniformly stretched condition and which removing operation may non-uniformly stretch successive portions of the filament, passing the filament so removed through a zone in which it is permitted to assume and at all times remain in an unstretched condition, varying the rate of feed of the filament into said zone in accordance with the amount of relaxation which the filament under-- goes in said zone without tensioning the filament in said zone to maintain the extent oi said zone of relaxation substantially constant, the filament within said relaxed zone being free from any weight other than its own weight at all times, and passing the filament from said zone in a substantially unstretched condition to 2. using operatlon.

B. A process for handling elastic filaments oi the type employed in the fabrication of textiles wherein substantial uniformity in physical characteristics of the filament is essential, comprising removing an elastic filament from its support whereon the elastic filament may exist in a nonuniiormly stretched condition and which removing operation may non-uniformly stretch successive portions of the filament, passing the filament so removed through a. zone in which it is permitted to assume and at all times remain in a substantially untensioned condition, varying the rate of feed of the filament into said zone in accordance with the amount of relaxation which the filament undergoes in said zone to maintain the extent of said zone 01 relaxation substantially constant, the filament within said relaxed zone being free from any weight other than its own weight at all times, and passing the filament from said zone in a substantially unstretched condition to s. using operation.

9. A process for handling elastic filaments which comprises removing a filament from its support, passing the filament so removed through a zone in which it is permitted to assume, and at all times remain in, a relaxed condition, utilizing displacement of at least a part of the mass of the filament within said zone, due to relaxation of the filament within said zone causing a temporary shortening in the length of the filament within said zone, to vary the rate of feed of the filament into said zone in accordance with the amount of said relaxation to reestablish the length of the filament in said zone, said filament/within said zone being free from any weight other than its own weight at all times, and passing the filament from said zone in a substantially untensioned condition to a using operation.

10. In a strand-tensioning device, in combination, a supply spool carrying the strand, a let-oif device, feeding rolls engaging the strand, means for applying energy to the feeding rolls to drive the rolls to pull the strand out from said spool and at all times maintain a loose, untensioned loop between the rolls and said let-ofi device, and means operated intermittently in response to shortening of said untensioned loop for increas-- ing the energy applied to said feeding rolls to increase the length of the loop, said filament within said loop being free from any weight other than its own weight at all times.

11. A process for handling elastic filaments comprising passing an elastic filament to a first feeding zone, passing the filament to a second feeding zone while permitting the filament to relax between the two feeding zones to a substantially zero state of tension, the filament between the two feeding zones being free irom any weight other than its own weight at all times, increasing the rate of feed of the filament at the first feeding zone in direct proportion to the amount of contraction in the filament between the two feeding zones, and passing the filament from the second feeding zone to a using operation.

JOHN M. amen. 

